Types of chemical reactions

A chemical reaction is a chemical change which results in the formation of one or more products. The initial reactants that are taken differ in physical or chemical characteristics from the products formed. Chemical reactions generally involve either the formation or the breaking of chemical bonds.

The different types of reactions are:
Direct combination reaction also known as synthesis reaction:
In this kind of reaction two or more products combine to form one complex product.
The general form can be represented by -

A + B → AB

Example –
2Fe + 3Cl2  2FeCl3

8 Fe + S8 → 8 FeS
Decomposition reaction also known as analysis reaction:
In these kinds of reactions, one compound is broken down into two or more simpler compounds.
Its general form is -
AB → A + B

Example-
Cu(CO3)  CuO + CO2
2 H2O → 2 H2 + O2
Single displacement or substitution reaction:
In these kinds of reactions one element displaces another form a compound to form a new compound and the displaced element. Generally the more reactive elements displace the less reactive element in a compound.
General form –

A + BC → AC + B

Example-

Zn + H2SO4  ZnSO4 + H2

Zn + 2 HCl → ZnCl2 + H2

Double displacement or double decomposition reaction also known as metathesis:

In these kinds of reactions the two reacting compounds exchange their radicals or ions to form two new compounds.

General form-

AB + CD → AD + CB

Example -

ZnO + 2HCl  ZnCl2 +H2O

NaCl(aq) + AgNO3(aq) → NaNO3(aq) + AgCl(s)
A type of double displacement reaction is an acid base reaction:
As the name suggests these kinds of reactions occur between an acid and a base. It is a neutralization reaction and is characterized by the formation of a salt and water. The hydronium (H+) ion in the acids reacts with the hydroxide (OH-) ion in the base to form these products.

General form Example –

HA + BOH → H2O + BA

Example-

HCl + NaOH  NaCl + H2O

HBr + NaOH → NaBr + H2O

Redox Reaction or Oxidation – Reduction reaction:
In these kinds of reactions both oxidation and reduction take place simultaneously in the reaction. Oxidation is characterized by addition of oxygen or an electronegative element and removal of an electro positive element, while reduction is the absolute opposite of this. It involves addition of hydrogen. In general oxidation is characterized by loss of electrons while reduction is characterized by gain of electrons.
Example of redox reaction-

2 S2O32−(aq) + I2(aq) → S4O62−(aq) + 2 I−(aq)
Here I2 is reduced to I- and S2O32- is oxidized to S2O4    2-
Hydrolysis Reaction:
This reaction involves water. General form is -

X-(aq) + H2O(l) ↔ HX(aq) + OH-(aq)
Isomerization reaction:
In these kinds or reactions the structural arrangement of a compound is becomes altered.
For example-
CH3- CH2-CH2-CH3 —> CH3

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CH3-CH-CH3

What are Neutralization Reactions?

Neutralization reaction refers to acid and base reaction producing salt and water. The equivalent amounts of acid react with base to form equivalent amounts of salt and water. When the reaction is complete, acid and base are said to neutralize each other. Since water is produced, neutralization reaction is also referred as “water forming reaction”. … Continue reading

Neutralization Reactions Between Acids And Bases

In a typical acid-base reaction the acids and bases combine to form salt and water. A salt is any compound which can be derived from the neutralization of an acid and a base. Such a reaction is called neutralization reaction because the acid and base properties of H+ and OH- are destroyed or neutralized. In … Continue reading

What are ionic equations?

The ionic equations, which are used for single and double displacement reactions occurring in aqueous solutions, are actually chemical equations in which the electrolytes are written as dissociated ions. For example, the ionic equation for the double displacement reaction of Calcium Chloride with Silver Nitrate in an aqueous solution would be: Ca2+ + 2Cl− + … Continue reading

Knowing About Photochemical Reactions

Any reaction that takes place in the presence of light or any other form of radiation is called photochemical reaction. A photochemical reaction is a chemical reaction that is induced by light. Photochemical reactions are valuable in organic and inorganic chemistry because they proceed differently than thermal reactions. Photochemical reactions are not only very useful … Continue reading

Why do we balance chemical equations?

The basic unbalanced reaction which portrays what elements have combined and what elements have been produced is called the skeletal equation. Knowing the skeletal reaction equation we know what the reactants are and what are the products, but for quantitative predictions we need to balance the reaction equation. The law of mass conservation states that … Continue reading

Identifying different parts of a chemical equation

The different parts of a chemical reaction involve the reactants, the products, the co-efficients and the subscripts. The reactants are the elements or compounds with which we begin the reaction. The products are those which are formed after the reaction. Co-efficients are the numbers present before the reactants and products indicating the number of moles … Continue reading

Factors affecting the rate of a chemical reaction

It is very much possible to be able to determine the rate at which a chemical reaction proceeds as there are various factors which can either speed up or slow down the rate of a chemical reaction. This article lists all those factors that affect a chemical reaction’s rate: Concentration of Reactants: higher concentration results … Continue reading